Hello,

I have been looking into your question and a topic about Freezing and Splitting Panes that you might consider could be found here. As it is suggested there, in order to freeze rows, you need to enable the panesAreFrozen property and then set the frozenRows count as follows:

  const worksheet = this.spreadsheet.workbook.worksheets(0);
    worksheet.displayOptions.panesAreFrozen = true;
    1;
    worksheet.displayOptions.frozenPaneSettings.frozenRows = 2;

If you require any further assistance on the matter, please let me know.

Sincerely,
Teodosia Hristodorova
Software Developer